Human colostrum, transitional and mature milk will be analyzed for micronutrient content and protective factors. Water-soluble vitamins will be assayed microbiologically and minerals will be quantitated by plasma emission spectroscopy. Immunoglobulins and lactoferrin will be assayed by radial immunodiffusion or by rocket electrophoresis. Lysozyme activity will be assayed turbimetrically, iron-binding capacity will be followed spectrophotometrically and vitamin B12 and folacin binding capabilities will be quantitated by adsorption methods using 57 Co-cyanocobalamin and tritium-labeled folic acid. Effects of processing and storage on the water-soluble vitamins and protective constituents will be determined. High temperature short time (HTST procedures and apparatus suitable for use at human milk banks will be developed.